Method and apparatus for the mechanical recording of sound oscillations



y 11, 1939- 7 P. c. RICCHIARDIR 2,166,079

METHOD AND APPARATUS FOR THE MECHANICAL RECORDING OF SOUND OSCILLATIONSFiled Nov. 6, 1936 6 Sheets-Sheet 1 INVENTOR.

# Pier (Er/0 Kfcchiardf.

AT TORNE Y.

July 11, 1939. 2,166,079

METHOD AND APPARATUS FOR THE MECHANICAL RECORDING 0F sounn OSCILLATIONSP. C. RICCHIARDI Filed Nov. 6, 1956 6 Sheets-Sheet 2 I N VEN TOR PierCar/o K/kchiard/ wmd ATTORNE Y.

y 1939. P. c. RICCHIARDI 2,166,079

METHOD AND APPARATUS FOR THE MECHANICAL RECORDING OF SOUND OSCILLATIONSFiled Nov. e, 1936 6 Sheets-Sheet s A no ATTORNEY July 11, 1939. P. c.RICCHIARDI 2,156,079

HETHOD AND APPARATUS FOR THE MECHANICAL RECORDING OF SOUND OS CILLATIONSFiled NOV. 6, 1936 6 SheetSSheet 4 ATTORNEY y 1939. P. c. RXCCHIARDI2,166,079

METHOD AND APPARATUS FOR THE MECHANICAL RECORDING 01 SOUND OSCILLATIONSFiled Nov. 6, 193 6 Sheets-Sheet 5 m ga I. NV EN To Q P/r, Car/olF/CCh/drdf.

BYW/

ATTORN EY July 11, 1939. P. C.RICCHIARDI 2,165,079

METHOD AND APPARATUS FOR THE MECHANICAL RECORDING OF SOUND OSCILLATIONSFiled NOV. 6, 1936 6 ShitS-ShGi-Bt 6 Fly B 17 a 23 I INVENTOE. P/erCar/o Aicch/ardf.

Patented 1 1, 1939 UNITED 'sTATE-s PATENT orrlca LATIONS METHOD ANDAPPARATUS non THE ME- CHANICAL aeooanmo or SOUND osom- Pier CarloRicchiardi, Paris,- France, assignor to the society Rcterson Holding",Paris, France Application November s, 1936, Serial No. 109,413 "1Claims. (01. 274-11) 'It has already been proposed to record, in acontinuous manner, sounds on a film; the latter unwinding from a ,spooland winding up on another reel, the continuity of the recording beingensured by reversing the working of .the motor.

A The object of the present invention, on the contrary, is to provide anapparatus permitting to record sounds on a film -by means of anengraving member, the film winding and unwinding in a continuous mannerupon itself by passing several times in front of the-engraving memberalways in the same direction, which permits of .ing type include arecording member and, eventually, a reproducing organ; One of these mem---bers serves to trace the phonographic.oscillations upon the supportand the other serves to the reading of these oscillations. If severalsound sources are simultaneously recorded, a mixin and a dosing of thesevarious sources in certain proportions of sound intensities-is effectedthen recording is effected on a single track which gives, duringrecording, a resultant of the different sound sources.

However, it happens frequently enough that, on account of a' defectivedosing or even of mistakes made during the recording, it is necessarytomake a correction. No known method permits of performing suchcorrections, so that it is necessary to effect a new recording:

-. This new recording is pdssible in cinematographic works, where thesame record can be repeated over and over, but, on the otherhand, it iswholly impossible when recording an interview 'or a ceremony forbroadcasting purposes, al-' though such recordings are often defectivebecause unforeseen events often occur.

The object of the present invention'is toobvijate .these drawbacks. Itis more especially intended to permit, after recording of thephonograms, of performing the necessary corrections without interferingwith the other records already.

taken.

The present invention is essentially characterized in thatthe-reccrding-is efiected along a' pluralltyof tracks, corresponding tothe respective sound sources, on a common support.

--. Therefore, when the sounds are reproduced, it is easyto observe thequality of the mixture of the respective elementary records. It is thenpossible to wholly eliminate one of these records and to correct it orto replace it by a new record which will also be traced upon thesamesupport. The invention therefore consists in a new arrangement ofthe soundtracks on a support, especially on a film, in such mannerthatit becomes possible, after recording of the sounds from varioussound sources, to correct, modify, and even replace one of thesoundtracks, which is found to be defective, by one.or several new soundtracks, without interfering with the other. sound tracks. a z

This result is obtained by providing a numberof recording andreproducing members equal to the number of sound tracks to be recordedupon the common record support, which may be a film or a disc.

Other features of the present invention will result from thefollowing'detailed description ofsome specific embodiments .thereof.

-Preferred embodiments of the present invenofv an apparatus according tothe invention;

Fig. 4 isa' plan view of this apparatus Fig. 5 is an axia-lisectionofthe film supporting a simplified apparatus for recording on an end-Figs. 6 and '7 show in elevation and in plan view respectively thesupport of the engraving or reproducing members;

Fig. 8 is a section through the axis of lateral displacement of theengraving member of a control device according to a first embodiment;Fig. 9'relates to another embodiment;- Figs. 10 and 11 show, in frontview and in axial sectional view respectively, the roller on which thesounds are recorded;

Fig. '12 is a plan view of a piece 'of a film re I corded according tothe invention;

I Figs 13 and 15 are three diagrammatical views I explaining theprinciple of recording and repro duction according to the invention.

. The simplified apparatus shown in Figs. 1 and 2- essentially comprisesan endless ribbon or film which is unwound from reel 2, in the directionindicated by the arrow, between two rollers 4 and 3. These rollers are apart of the whole constituting the central core of the reel fixed onmagazine I3. These rollers are free to turn on their axis and the rotarymovement with which they are moving is imparted thereto by ribbon Iwhich acts by friction whereas the last spire of this ribbon unwindsunder the action of a traction. Ribbon I leaves the magazine in anoblique direction. It is straightened up by a roller 3 in such manner asto be brought in the axis of drum 5 upon which it bears and along whichthe recording is effected by means of an engraving style 8.

When passing between the straightening roller 3 and drum 5, filmor'ribbon I rubs through its edge against the roller of a detector 4which ,is intended to laterally displace the engraving For this purpose,this ribbon is provided along its edge with a notch which, upon itspassage;

permits the detector 4 to oscillate and to release a relay, as it willbe hereinafter explained.

From drum 5, ribbon I engages between a pulling roller 6 and a pressingroller 'I mounted loose upon its axis. The pressure of this roller Iupon pulling roller 6 is easily obtained by means of a spring I Thepulling roller 6 is covered with rubber so as to exert without slippingits pulling action upon ribbon I.

Upon leaving compressing roller I, the ribbon goes back to reel 2 andautomatically winds along the outer periphery of the latter.

The recording tool 8 is carried by an arm 9, pivoting at I2; This arm 9is connected to a trailer I5moving with a lateral movement. ThistrailerI5 is controlled by a sector I8 which includes as many teeth as thereare sound traces to be recorded upon the surface of the ribbon.

An electrical device II, which will be hereinafter described, serves toactuate sector I8 which, in turn, controls the displacement of therecording tool 8 at each passage of the notch provided for this purposein ribbon I.

An embodiment of the electric control device for the lateraldisplacement in a step-by-step manner of the engraving member is shownon the diagram of Fig. 2.

In this system, the displacement from one sound track to the other musttake plaoebefore' the 'end of the full cycle of the ribbon thatconstitutes the support, because otherwise, there would be a risk of twosound tracks being superposed, which would therefore destroy a part ofthe first recording. I

In order to avoid the overlapping of two sound tracks, theelectro-magnet controlling the displacement of the engraving membershould work with a great rapidity and a great regularity, which ispractically difllcult to obtain.

In order to eliminate this drawback, according to the presentinvention,.the displacement of the engraving tool for each full cycle ofthe ribbon is effected with a slight delay before this cycle iscompleted which provides for the continuity of the recording withoutstopping or overlapping.

In other words, it is supposed that the notch intended to bring intoplay the device for displacing the engraving style comes oppositedetector 4 (Fig. 2) and that the surface of the ribbon permits oftracing thereon twenty sound tracks. The displacement of the engravingtool takes place in this case with a difference corresponding to twentyunits of time for the first track. At the second passage, there is adiff rence of I9 units of time before the transverse displacement; forthe third passage, the diflerence will be I8 units of time and so onuntil the surface'of the ribbon is fully covered.

With this device it is found that a useful margin is obtained in thetransverse displacement of the engraving tool,.this margin correspondingto one unit of time for each full cycle of the ribbon and therefore asufiicient period of time for obtaining a deviation of the sound trackbefore its meeting with the preceding track.

Ribbon I operates two contacts 4 4 of detector 4 which are appliedagainst each other when the notch of ribbon I is passing. When contacts4 4 are closed, the negative source of the electric feed which arrivesto contact 4" passes to contact 4 -through conductor III, to thenegative terminal of the electro-magnet, flows through the coil I82 ofthe latter and passes to the positive source I83.

The electro-magnet I82 is operated, its armature I82 is attracted andacts upon lever I82" which pivots about an axis I 82 in the direction ofarrows f and f In the course of its ocillation, the end I82 of lever I82closes the negative circuit I81 through the making of contacts I89 andII 8.

In "the meantime, the notch of ribbon I has passed and contacts 4 4 areagain open and thus cut' off the negative feed of electro-magnet But amaintaining circuit has been established by lever I82 and conductor I81,contacts I89 and H8, and conductor II2, itself connected to the negativeterminal of the electro-magnet I82.

As lever I82 remains in its position of attraction, the end I I4 of thelatter acts against toothed wheel II5, which is kept in constantrotation by a motor H6 of any type.

Due 'to the efiect of the pressure of part II4 against the externaledges of-wheel II5, the latter, which is elastic bears through itsopposite side I I1 against the surface of a friction wheel I22. The twoaxes H8 and H8 being thus interconnected, cylinder I28, carried byspindle H9, is set in rotation.

On cylinder I28 are helically mounted electric. contacts I'23a, I231),I230, I23x. The number of contacts I23 on cylinder I28 is equal to thenumber of sound tracks to be traced upon the surface of the ribbon.

All these contacts I23 are connected to the negative mass I26. CylinderI28 being set in movement, contact I23a comes into contact with brush 24only after a certain time.

It will then be noted that, in order to obtain the desired timedifference between each displacement of the engraving style, contactsI23 fixed on cylinder I28 are disposed along helix I25, determining foreach of them a different and diminishing unit of time. This time isregulated by the speed of the spindle N9 of drum I28.

Contact I23a and brush I24 constitute a negative circuit which, startingfrom mass I26, contacts I23a, brush I24, conductor I21, the coil ofelectro-magnet I28, and conductor I 28, is closed on the positiveterminal I38. Y

Consequently, electro-magnet I28 is energized and attracts its leverI3I. The end of this lever I3I carriesa, pawl I32 whichcauses sector I8(Fig. 1) and therefore screw I34, to move a distance corresponding to atooth. Under this action, engraving element 8 moves a distance equal tothe space between two grooves, At the same time, brush I24, which isfixed to the trailer, moves the 1 given merely by way of example and itmay be substantially va'ried.

same distance. On the other hand, the displacement of lever'I3I releasescontact I35 and cuts off the positive source I30 which feedselectro-magnet I02. .Finally, a sudden breaking of the feed circuit ofeiectro-rnagnet H8 is obtained, since contacts I23a and brush I24 are nolonger in electrical connection.

- However, it will be noted that the cutting off of the feed ofelectro-magnet I28 permits lever I02 to come back into its position 'ofrest under releases toothed wheel I I5 which in turn, by ceasingto rub,against the disc I22, causes drum IZII to stop.

Therefore, the engraving style 8 has been moved along the ribbon adistance which is accurately determined and corresponds to the ro'tationof a tooth of sector In and therefore to the distance between twosoundtracks.

This displacement is ensured'with a delay with respect to the closing ofcontacts 4 4 of the detector, this delay being equal to the number of'units determined by .the number of contacts mounted on cylinder I20.This delay will a ways go diminishing since the-rotation of cylinder I20is uniform. I -Through this arrangement, I obtain the displacement ofthe style in a discontinuous manner for each cycle of the ribbon, with asufiicient lag for controlling all tolerances in the electric ormechanical precision of relay I02 controlled by the closing of contacts4 4 this lag being amply sufiicient for ensuring the continuity of thesound grooves, without any'risk of overlapping.

The simplified apparatus described with refcrence to Fig. 1 may undergomany modifications and variations without'depa'rting from the'principleof the invention.

For instance, I will hereinafter describe a more complete apparatus,which includes other char:- acteristic features which are of interest.

Fig. 3, which shows the whole of this apparatus shows the endless ribbonI, which unwinds from reel 2 in the manner above described withreference to Fig.1.

The magazine supporting reel 2, which more particularly shown in Fig. 5,is characterized by the following feature: The reel of endless ribbonLbears upon rollers 3, which are free to rotate upon their axis. Thereel engages, with a lateral friction, a disc 50 which is given a rotarymovement imparted by grooved pulley 5i driven by the engine.

Rollers 3, which constitute the magazine, have .the same direction ofrotation as the film, andv move together with it in its movement, whichpermits the latter to easily disengage from its magazine without anyjamming, as would other-- wise occur if this 'central core wereconstituted by a single ring turning freely about the axis of themagazine.

The number and the diameter of rollers 3 are determined by the innerdiameter that is chosen for reel 2, which diameter is alsodirectlypropor tional to the number of spires which determines thelength of the film. As a rule, the ratio of the inner diameter and theouter diameter'of the reel will be This ratio gives'a resistance totraction sufficient for the correct recording of the oscillations,

without producing any appreciable deformationof the support that isemployed. This ratio is In order to'reduce the tension of the ribbon asit leaves the magazine, .the rotary disc 50 (Fig. 5) upon which reel 2bears helps the latter to turn in its magazine.

The tension of the ribbon, upon its leaving "of that due to the tractionexerted upon the ribbon.

This movement will be the more important as the required pressure issmaller and, consequently, the pressure exerted in the reel is inverselyproportionalto the speed of revolution of disc 50. The endless unwindingthus obtained is not based upon the natural reaction due to theelasticity of the ribbon but merely to the reaction due to the gradualtightening of the spires of the ribbon while the latter in unwindingunder the effect of a traction.

This device has the advantage of eliminating, during the recording, thetwo reels and all the devices for reversing the working, the purpdsepfwhich is to obtain an uninterrupted recording and reproduction ofoscillograms including multi-.

ple tracks upon a common ribbon, as it will be hereinafter explained. Itpermits also the use of a ribbon of indefinite length for a spaceoccupied reduced to a minimum.

The apparatus of Figs. 3 and 4 also includes a group of two engravingtools the detail of which is more especially shown by Figs. 6 and ,7.

This system permits of carrying out the process of recording onsimultaneous multiple tracks.

It may also be employed as recorder and reproducing system. In thelatter case, one of the organs will be used for recording and the otherfor reproducing which then permits immediate, reproduction of theoscillograms that are recorded.-

This system includes two recording or reproducing members 8 and fi fixedupon a common frame 63, which-is itself displacedlaterally by a trailer66. These two recording and reproducing members 8 and 8 are pivoted toframe ta through pivots l5 and it.

On the other hand, the apparatus includes two drums for inscription 5 5instead of a singleone as in the apparatus of Fig. 1. These drums 5 5act as supports for styles]? and i8 and as bases for the ribbons whichunwind upon their surface by passing along an intermediate roller 69 Oneof the two engraving elements 8 can move transversely to the ribbonindependently of the other engraving element 8 For this purpose,

.the connection between frame 63 and the intermediate support II- isobtained through a screw 12 fixed by pins .13 and 14 to the frame.

'In order to obtain a transverse displacement of engraving element 8with'respect to engraving element 8 it suflices to act upon handle I5(Fig. 7) keyed .upon screw 12, which, due to its rotation, displaces thedesired distance the support II and also'engraving element 8 This systemworks in the following manner: (a) Fdr the recording and the immediatereproduction of sound oscillogranis, ribbon l, the direction of movementof which is given by the direction of the arrow, passes between drum 5ments along the axis of track Q3 and to repeat .port 9.

and the style 11 of the recording element 8 Ribbon l receives the soundrecord from this recording element. When leaving drum 5 ribbon l engagesbetween drum' 5 and style 78 of the reproduction organ 8, by passingfirst along the intermediate roller 69. The latter has for its object todestroy the mechanical vibrations which might occur when the ribbonleaves drum 5 Both of the styles 1'! and 18 being disposed on the sameaxis and in the same channel,- it is possible to perform, with a verysmall lag, the reading of the sound oscillograms traced in the supportby the recording element 8 Fig. 13 shows the arrangement of therecording and reproducing styles I1 and 'l8 on the support I.

(b) For the simultaneous recording and reproduction of two tracks fromtwo different sound sources, the engraving element 8 is displaced withrespect to the engraving style 'l'l a distance equal to the spacebetween two tracks. In this way, I obtain with both styles, during therecording, two tracks parallel to each other.

Fig. 1% shows the position of the two engraving styles it and t8 and thetracks formed on sup- 1 have shown at H the tracing of an auxiliarytrack which is reserved, after recording, and in case of need to replaceone of two preceding ones, according to the method above set forth,

Fig.15 shows how reproduction is efiected with an auxiliary track 'illreplacing track TI, which has for instance given a defective record. Inthis case the tworeproducing members ll and 18 are disposedindependently of each other upon traces H and it, by transversedisplacement of style it, as above explained.- r

The invention also includes this method of recording, whatever be themethod of obtaining the sound tracks and whatever be the nature and theform of the support (film or disc).

Fig. 12 shows, for instance, a portion of a ribbon the tracks ti, Maud9U, Q2 of which, running parallelly and in the form of spirals,

' have been traced by a device consisting of two recording members, eachof these tracks representing the recording of an independent soundsource. Tracks 93 and 93' represent the available auxiliary tracksintended for the replacement or one of the two preceding tracks.

Of course, the number of these auxiliary tracks may be higher than onewithout, for this reason, departing from the principle of the invention.

In order to better explain the usefulness and the technical value of theinvention, I will hereinafter describe a practical example of arecording on a band, with parallel tracks.

It will be assumed for instance that two different sources are recordedat M and 92. Track 9| corresponds to the sonorous background record, andtrack 52 corresponds to a speech explaining these sounds and made by aspeaker. Assuming that track, 92 must not be used and a new track mustbe substituted in place thereof,

it sufiic'es to displace one of the recording elethe speech. Whenreproducing, the reproducing elements will be placed on tracks at and93, track 92 being left alone. J

The invention therefore permits of eliminating the chief defect of theactual technic of phonographic recording, by permitting:

- (a) A true making up. .of the recorded sounds; (b) The mixing 0t thesevarious sources after recording;

(0) The replacing of the correcting of the recording of one or severalsound sources.

It has been above explained, when describing the apparatus of Figs. 1and 2, that the engraving element could be displaced periodically, in adiscontinuous manner after a complete cycle of the ribbon.

In this case, the sound tracks are parallel to one another and at theedge of the ribbon. The displacement of the engraving element may beensured either through mechanical means or through electrical means, asexplained with reference to Fig. 2.

It is also possible to displace the engraving style in a gradual mannerand proportionally to the speed of unwinding of the ribbon.

In the latter case, the tracks are of spiral shape and parallel to oneanother. For this purpose, the engraving style is given a continuousmovement proportional to the movement of the ribbon.

v A first embodiment of this mechanism is shown In Fig. 8. The controlof this mechanism is obtained from drum 5, which is itself driven by themoving film.

The transverse displacement of the engraving style is continuous andproportional to the length of ribbon contained in the magazine. Thisdisplacement is extremely small with comparison to the speed of drum 5,which constitutes the driving part, and accordingly there is provided aspeed reducing gear 202.

This reduction of the speed of the drum is calculated in such manner asto displace, for each complete cycle of the ribbon, the engraving stylea distance equal to the interval between two sound tracks in the axialdirection.

The trailer includes;

A frame 63-on which is fixed the engraving element 8;

A helical pitch screw 64 in line with which are fixed the last reductionstage 201 and sector 206 which acts as a marking element for therecorded tracks;

.A guide 205, fixed to-two supports 208 and 209 permitting thetransverse displacement of the trailer, while ensuring the absoluterigidity there- The movement transmitted by ribbon l to drum 5 isreduced by system 202-201 and is transmitted to screw 64, which ensuresa slow disto the distance between two sound tracks for one cycle of theribbon, which determines a spiral shaped tracing upon the surface of theribbon, these tracks being parallel to one another.

As this reduction is calculated with reference to the length of ribboncontained in the magazine, it becomes impossible to increase or reducethis length without .varying, in a corresponding manner, the ratio ofthe reduction because, the pitch of the helix engraved in the supportbeing proportional to the length of ribbon, if the length in questionwere considerably reduced, this would involve causing adjacent tracks tooverlap one another and to destroy the phonograms that are recorded.

The modification of Fig. 9 avoids this drawback by permitting ofchanging the gear ratio of screw 64. This modification thus permits ofkeeping the same distance between two tracks for any length of ribbon inthe magazine.

This device includes, as chief element, a flywheel Eii one of'the facesof which is covered placement of the engraving style corresponding.

with an adhering material 2l2, which may consist of rubber.

Fly-wheel 2 slides on the axis 2"! of drum 5 and through the'medium of akey 2l5 fixed to spindle 2|0 it is given a rotary movement by this Aspring 225 is intended to increase the therefore obtained by thedisplacement, along the axis 2, of wheel 2l3, its movement being limitedby A B. Point B corresponds to the smallest gear ratio-and point A tothe highest ratio.

The apparatus of Fig. 3 also includes a device permitting of adjustingthe pressure of the engraving element on the film and of modifying thecutting angle of this engraving element.

For this purpose (Fig. 11) the record drum which constitutes a supportfor ribbon I when sounds are recorded or reproduced, is carried by aspindle 233 slightly eccentric at 234. This eccentric spindle 233turnsin a bearing 231 which is a part of the frame of the apparatussupporting the other elements.

Spindle 233 is braked by a spring 238 which is calculated in-suoh manneras to oppose the reaction due to therotation of drum 5 and to thetraction exerted thereon by ribbon I. Drum 5 turns loose about itseccentric spindle 233. A groove 233 has been provided for being filledup with hard rubber giving said drum the elasticity necessary for a goodrecording of the sound oscillograms.

A control handle 235 produces, when turned, the rotation of spindle 233,which displaces drum 5 along a circle (Fig. 10) the center of which willbe at an equal distance from O and 0 and the diameter of which is equalto (AB). 00 is the minimum-displacement and OB the maximum displacementof this eccentric.

The starting of the apparatus is ensured in a particularly simplemanner; by means of a control knob 305 actuating alever 30% (Fig. 3) onwhich is mounted the compressing roller 5 the pressure of which uponribbon 9 causes the adhesion of this ribbon to driving roller ii,actuated by motor 3M.

Finally the whole of the apparatus, a plan view of which is given byFig. 4, can advantageously be completed, eventually, by a vacuum devicefor removing cuttings;

Fan are is driven by the motor 309 of the apparatus. This fan includes asuction nozzle disposed close to the engraving styles-and blows thecuttings into a box 302 disposed at the rear of the apparatus.

While I have, in the above description, disclosed what I deem to bepractical and efiicient embodiments of the present invention, it shouldi sound oscillations with linear tracks, which comprises a stationaryframe, two electromechanical organs carried bysaid frame and havingengraving members for recording and reproducing sound oscillograms, anendless film serving for supporting the record, means for winding andunwinding in a continuous manner said endless film on a reel and passingit against said engraving members, in such a manner that one of saidelectromechanical organs working as reproduceipermits to control therecord made by'the other, and a device for moving transversely withrespect to said endless film one of said two electromechanical organs inorder that it describes a new track.

2. An apparatus for mechanical recording of sound oscillations and forreproducing of sound records, which comprises a stationary frame,

- electromechanical organs carried by said frame and having engravingmembers for recording and reproducing, an endless film which serves forsupporting the record, means for winding and unwinding in a continuousmanner said endless film on a single reel and passing it against saidengraving members, a rotary disc applied against the edges of thespirals of said reel and means for-driving said disc in order to give ita peripherical speed at least equal to the unwinding speed of the film,in the same direction as that of the movement which said film, whenunwound, tends to communicateto said reel.

3. An apparatus for mechanical recording of sound oscillations, uhichcomprises a. stationary frame, electromechanical organs carried by saidframe and having engraving members for recording, an endless film whichserves for supporting the record, a device for winding and unwindingsaid endless film on a single reel and passingit against said engravingmembers said device comprising a traction friction organ acting on saidendless him, a rotary disc applied against the spirals of said reel andmeans for driving the rotation of said disc in order to give it aperipherical speed at least equal to the unwinding speed of said film,in the same direction as that of the movement which said film, whenunwound, tends to communicate to said reel, and

means for transmitting rotation from said traction organ to said rotarydisc.

4. An apparatus for mechanical recording of sounds, which comprises astationaryframe, an

endless film, electromechanical organs with engraving members carried bysaid frame for recording on said film and means for giving to saidengraving members a transverse displacement-by jerks at the end of eachcomplete revolution of said film, saidmeans comprising a delaying organintroducing in the drive of said displacement a decreasing delay fromone revolution to the following.

. 5. An apparatus as claimed in claim 4, in which the means for givingto the engraving members a transverse displacement "at each revolutioncomprise a friction roller driven in rotation by said endless'film atand a reducing gear driven by said wheel. r

6. An apparatus as claimed in claim 4, in which the means for giving tosaid engraving members a transverse displacement at the end of eachrevolution comprises a friction roller driven in rotation by saidendless film and a reducing gear driven by said friction roller andprovided by an adjustable organ for controlling and regulating withprecision the proportion between the transverse displacement and theunwinding time, in order to maintain in suitable limits the distanceseparating two successive sound tracks on said endless film.

'7. An apparatus for mechanical recording of sounds, which comprises astationary frame, an endless film, means for winding and unwinding saidfilm in a continuous manner, electromechanical organs with engravingmembers carried by. said frame for recording on said film, a drum onwhich passes said film against said engraving members, an axle carryingsaid drum and means for rotating said axle, in order to adjust theapplying Iorceof said engraving members against said film.

- PIER. CARLO RICCHIARDI.

